The full-duplex communication is not a new issue, but why the current wireless networks are still half-duplex channel link, Time Division Duplex (TDD) or Frequency Division Duplex (FDD), is that there may be a lack of feasible solutions in hardware for wireless full-duplex radio in the past. However, some research groups start and succeed to propose feasible solutions and design a real full-duplex radio system in recent years.
Nowadays, the frequency band below 5 GHz has become extremely scarce, so improving spectrum efficiency or finding new frequency band is needed gradually for future wireless networks. Current wireless networks are often operating on the TDD system or the FDD system because a base station (BS) may only transmit or receive at one time and at same frequency band. When operating in a TDD system, both the transmitter and the receiver use the same frequency but transmitting operation and receiving operation are switched by time. While operating in a FDD system, two different radio frequencies are used for transmitting operation and receiving operation, respectively. With the full-duplex capability, the BS can simultaneously serve uplink and downlink clients at same time and at same frequency band, so the full-duplex networks may have the potential to double spectrum efficiency theoretically.
However, different from half-duplex networks/communication systems, a base station operating in full-duplex networks has now to serve uplink and downlink clients simultaneously, so the procedure of performing the configuration and the measurement will be different.
Therefore, it is becoming a design consideration on how to perform full-duplex communications in the current wireless networks or future wireless networks.